The present subject matter relates generally to method for the removal of acetaldehyde in the presence of other oxygenates from feedstocks. More specifically, it relates to methods for the removal of acetaldehyde using an amorphous sodium-doped alumina derived from thermally decomposed Dawsonite (sodium aluminum carbonate hydroxide).
Feedstocks derived from fluid catalytic cracking processes used in industry should be produced to be as pure as possible without the presence of contaminants. Conventionally, acetaldehyde is a common contaminant in C4 fractions of such feedstocks. The purification of the feedstock is needed for many refining and petrochemical applications. Acetaldehyde is known to be particularly problematic toward downstream catalytic processes due to a potential for condensation and polymerization reactions. Furthermore, acetaldehyde is a health hazard to humans as a possible or probable carcinogen. High acetaldehyde contamination can lead to deactivation of zeolite based adsorbents towards removal of other contaminants due to preferential adsorption of acetaldehyde.
Adsorbents selective to adsorb oxygen containing organic compounds are typically known in the prior art. The oxygen containing organic compounds include various contaminants such as aldehydes, ketones, esters, alcohols, etc. The conventionally employed adsorbents are not effective for efficient removal of acetaldehyde. The selective removal of acetaldehyde has been difficult to achieve with zeolite based adsorbents due to their affinities to various oxygenates that may be present along with the acetaldehyde contaminant in the feedstock. The presence of acetaldehyde renders the feedstock undesirable for many commercial applications. Therefore, there is a need for an improved adsorbent that is selective for removal of acetaldehyde in the presence of other oxygenates as well as nitriles which also are usually preferentially adsorbed to acetaldehyde.